The ISO/IEC 19763 family of standards defines normative metamodels for the registration of models (including information models and process models), ontologies, services and roles & goals. Currently a lot of metadata registries or model registries were constructed and utilized in many different business domains, such as e-business, healthcare, automobile, electronics devices and civil construction.

One of the key issues for the cross domain data or services integration must be enabling the easy discovery of metadata that are stored in the different registries that were scattered over different domains. Therefore, it is necessary to provide specific metadata that describes the registry itself in order to enable interoperation among different registries that were built following different standards.

ISO/IEC 19763:2015 family of standards specifies an information artefact called the Registry Summary. The Registry Summary consists of information that describes administrative aspects, the summary of contents and the technical access method of the registry.

A collection of multiple Registry Summary information is called a "Registry of Registries" or RoR, however, this standard does not mandate a particular implementation. Also, any specific protocol between Registry Summaries and RoR, such as creation of RoR and synchronization of RoR, would not be specified in this standard. Those are to be specified by other standards.

The Registry Summary and RoR concept should be applied to all Metamodel Framework for Interoperability (MFI) registries, but its use may be applied to any kind of registries.